Difference in organic carbon contents and distributions in particle-size fractions between soil and sediment on the Southern Loess Plateau,China

The purpose of this study was to assess the effect of long-term cultivation and water erosion on the soil organic carbon （OC） in particle-size fractions. The study site is located at Nihegou Watershed in the Southern Loess Plateau, China. The soil at this site is loess with loose and silty structure, and contains macropores. The results showed that the OC concentrations in sediments and in the particle-size fractions of sediments were higher than those in soils and in the particle-size fractions of soils. The OC concentration was highest in the clay particles and was lowest in the sand particles. Clay particles possessed higher OC enrichment ability than silt and sand particles. The proportions of OC in the silt fractions of soil and sediment were the highest （mean value of 53.87% and 58.48%, respectively）, and the total proportion of OC in the clay and silt fractions accounted for 96% and 98% of the total OC in the soil and sediment, respectively. The loss of OC was highest in silt particles, with an average value of 0.16 Mg ha^-1 y^-1, and was lowest in the sand （0.003 Mg ha^-1 y^-l）. This result suggests that the fine particle-size fraction in the removed sediment may be an important indicator to assess soil OC losses.     

山东省黄河下游流域生态地球化学调查主要成果

农业地质环境调查成果表明,山东省黄河下游流域5．4万km^2的土地质量总体状况良好,绝大多数土地是清洁的。调查区内有99．9％的土壤为绿色土壤,可生产无公害小麦、玉米等农产品;一类土壤占92．7％,适宜于发展绿色食品生产;二类土壤占7．2％;三类土壤占0．1％。本次调查发现的重金属严重污染土地集中分布在城市的周边地区。浅层地下水地球化学调查结果表明,区内浅层地下水环境污染状况严重,水质优良的地段主要分布在济宁市区北、平阴周边、长清南、济南市区南部等靠近山前地段,其他平原地区的水环境质量多为较差或极差级（不能饮用）。     

山东黄河冲积平原区土壤地球化学特征

山东黄河冲积平原区土壤地球化学调查是按每1km^2采集1件表层土壤样品,4km^2组合成1件分析样品,每4km^2采集1件深层土壤样品,16km^2组合成1件分析样品,测试Ag,As,Au,B,Ba,Be,Bi,Br,C,Cd,Ce,CI,Co,Cr,Cu,F等54项指标。在统计这些指标的表层、深层土壤地球化学特征参数的基础上,对其与全国同类参数的差异进行了分析,对比区内表层、深层土壤元素地球化学含量值的变化,认为大部分指标在表层土壤中的含量继承了土壤母质的成分特征,后期人类活动对其影响较小,但Corg,N,Se,S,P,Br,Hg等指标在表层土壤中已明显富集,表明表生作用和人类活动等因素已对这些指标的分布分配产生明显影响。     

浅析我院论文发表现状——基于核心期刊的统计分析

作者从文献计量学角度出发，统计分析了成都气象学院建院１８年以来所发表的１３７４篇论文所显现的科研现状，指出了该学院在学科研究及论文发表方面的优势和不足，并对学院科研方向较为分散、论文影响力较小及科研后备队伍建设有待加强等问题提出了改进建议。     

黄土高原东部(山西阳曲)1.2Ma以来黄土记录的两次显著干旱化事件

重建第四纪时期亚洲内陆干旱过程和沙漠的扩张历史对于我们了解东亚冬季风演变具有重要意义.然而目前对于黄土高原的干旱过程的研究主要聚焦于吕梁山以西的黄土地区,对于其东部还缺乏相应研究.为此,我们对吕梁山东部约1.2 Ma以来的阳曲黄土剖面进行了磁化率和元素含量测试,结果显示阳曲地区在1.2 Ma以来经历了两次明显的干旱事件...     

Climatic Aridity and the Relocations of the Zhou Culture in the Southern Loess Plateau of China

Several Holocene loess-soil profiles at the archaeological sites of the political center, and later, the capital cities of the predynastic Zhou and Western Zhou Dynasty (ca. 1400–771 B.C.) inthe southern Loess Plateau were studied multi-disciplinarily. It provides insights into monsoonal climatic change and the relocations of the Zhou culture in this climatically sensitive semiarid zone. Both the analytical data and written records indicate that increased climatic aridity at 1150 B.C. induced a considerable environmental deterioration and degradation of natural resources, especially water shortages, decreases in precipitation and deficits in soil moisture. These resulted in poor harvest and great famines, plagues, domestic upheavals, population migrations, and even conflicts between Zhou people who subsisted on dry farming and nomadic tribes on the northern steppe during the development of the Zhou culture. It seems that persistent droughts forced Zhou people to move from the upland plateau to the lowland riverbanks step by step through relocations, following a direction of increasing climatic humidity, soil moisture, water availability and biodiversity. The southward migration of the nomads on the steppe of the northern Loess Plateau and the Mongolia Plateau in response to the climatic aridity was another dynamic force that caused the relocations of the Zhou culture.     

2009-2018年南黄海苏北浅滩海域漂浮浒苔和马尾藻现场调查研究

利用2009-2018年在南黄海苏北浅滩海域的现场调查数据,分析和研究了该海域漂浮绿藻和马尾藻的长期变化和季节性波动特征。研究显示,漂浮绿藻于每年4月中旬至下旬在浅滩中部筏架周围开始出现。5月－6月,漂浮绿藻生物量迅速增加,并漂移扩散至深水区。漂浮绿藻密度年际变化较大,但这十年间总体呈上升趋势。相比较而言,漂浮马尾藻仅在2013、2017和2018年在浅滩聚集形成春季藻华;且这三年,漂浮马尾藻密度超过同期漂浮绿藻。浅滩漂浮马尾藻的发生与发展过程与漂浮浒苔明显不同。3月,漂浮马尾藻开始出现于浅滩离岸海域,4-5月,漂浮马尾藻大量侵入浅滩,因此浅滩漂浮马尾藻现并非起源于本地。受高强度人类活动以及浅滩以外海域物理化学和生物过程的影响,浅滩环境因素与漂浮绿藻生物量的关系不甚明确。对于漂浮马尾藻的起源以及与漂浮绿藻的相互关系也需要进一步研究。     

φ600mm冲击钻头的设计与使用

作为当前探矿工程扩大服务领域一个重要方面的水井施工,一般以冲击钻进为主。本文较详细地介绍了一种新研制的冲击钻头的结构要素、加工工艺以及实际使用情况。     

毛乌素沙地风况及输沙势特征

利用毛乌素沙地腹地野外实测风速风向数据,系统分析了毛乌素沙地的起沙风和输沙势的变化特征。结果表明：（1）毛乌素沙地的起沙风和输沙势主要分布在NW、NNW和N等3个方位。（2）毛乌素沙地春季（3—5月）起沙风频率和输沙势最大,分别占全年的46.23%和52.97%。（3）起沙风频率的日内变化呈单峰曲线：16：00起沙风频率最大,为22.11%。起沙风平均风速的日内变化呈双峰曲线：00：00起沙风平均风速最大,为7.84 m·s^-1;14：00起沙风平均风速为7.63 m·s^-1,是次峰值。（4）毛乌素沙地年输沙势为66.75 VU,按照Fryberger风能环境划分标准,属于低风能环境;方向变率指数RDP/DP为0.51,中比率,钝双峰风况,其中偏北峰值远大于偏南峰值。     

Discussion on Petroleum Migration in Bamianhe Oilfield of Dongying Depression, East China

Petroleum migration process of Bamianhe oilfield of Dongying depression, East China is evaluated on the basis of our detailed work on geochemistry of the crude oil and the source. Molecular tracers, especially nitrogen compounds, are employed in assessing style of oil migration and accumulation. Additionally, absolute quantitative results of heteroaromatics including dibenzofuran, dibenzothiophene and fluorene with similar basic frames to pyrrolic nitrogenic compounds are also used to evaluate the quantity of petroleum migration. According to apparent migration effects of the pyrrolic nitrogen compounds, it is indicated that most of Bamianhe oil was derived from potential source kitchen-Niu-zhuang sag, migrated and accumulated at Bamianhe fault belt through selective paths according to a main filling point displayed. Generally, upward migration trend from the main point along the south slope is noted. There are observable migration effects from Guangli subsag to the north Bamianhe and Yangjiaogou oilfields showing Guangli subsag was a secondary kitchen accounting for the oils in the north portion. Significant vertical migration effects shown in several cross sections demonstrate that faults well developed in the area play an important role in oil migration and accumulation. Unformality, sandstone reservoirs distributed locally also suggest important fairways in connecting sources with traps. The tectonic and a combination of tectonic and lithological mechanism are identified as the critical mechanisms in entrapping hydrocarbons. Migration trend suggested by nitrogenic compounds agrees well with analysis of lateral compositional variety and thermal maturity gradient. This study also confirms well with our previous studies. It is the location of source rocks, tectonic and stratigraphic characteristics that have a comprehensive control on the model of hydrocarbon migration and accumulation in Bamianhe oilfield. Results also show that the oils are mostly derived from the deep parts of the Niuzhuang and Guangli sags within normal oil window.